You might not have noticed be­cause your brows­er does not prop­er­ly
support soft hy­phens. Or none of the words on the page needed any
hy­phen­ation when you looked at it. Or the effect was just to subtle and
nutural to catch your at­ten­tion. Or you didn't hear or feel anything
spe­cial. But the page which has this button on it is try­ing to use soft
hyphens to let browsers break words at certain points and improve the layout
that way.

If you're also using soft hyphens on your site to improve the layout you
might want to use the fol­low­ing code in your page to show the but­ton to let
people know you're trying to im­prove their ex­pe­ri­ence.